In this passage, the narrator reflects on her younger sister and imagines her future as a grown woman. Despite her age, she envisions her sister maintaining her innocence and kind-hearted nature, which she held as a child. The scene emphasizes a sense of longing and admiration for the innocence that remains unchanged over time.
She imagines her sister growing up while still preserving the qualities of simplicity and love that defined her childhood. This thought highlights the importance of staying true to one's genuine character, regardless of how much someone may change externally or with age.